Figure 3

Bayesian mixture analysis. a) Individual-based mixture analysis of 1225 Galápagos marine iguanas to 20 genetic clusters as determined by the program STRUCTURE following the estimation of true number of genetic clusters (K) following [44] Evanno et al. (2005; see Figure S1 [see Additional file 5]). Note that individual samples taken at two different time points (i.e. in 1991/93 and 2004) on an island location represent the same genetic cluster. With the exception of Fernandina and Isabela all major islands each represent a distinct genetic cluster. b) Population-based mixture analysis for the same number of genetic clusters according to STRUCTURE. For (a) and (b) the program DISTRUCT [45] (Rosenberg 2004) was used to generate the display genetic clusters and degree of admixture of individuals.